This is huge. Anti-matter is a tricky thing; when it hits its counterpart in regular matter, they two annihilate (never to be seen again).

An antihydrogen atom is made from a negatively charged antiproton and a positively charged positron, the antimatter counterpart of the electron. The objective — both for ALPHA and for a competing CERN experiment called ATRAP — is to compare the energy levels in antihydrogen with those of hydrogen, to confirm that antimatter particles experience the same electromagnetic forces as matter particles, a key premise of the standard model. “The goal is to study antihydrogen and you can’t do it without trapping it,” says Cliff Surko, an antimatter researcher at the University of California, San Diego. “This is really a big deal.”